Screening apparatus.



P. M. KUEHN.

SCREENING APPARATUS.

APPLICATION FILED DEC.29.1914.

Patented Nov. 2, 1915.

5 SHEETSSHEET 2.

mm a

io ooooo El No: we L 4.

P. M, KUEHN.

SCREENING APPARATUS.

APPLICATION FILED DEC.29. I914. I

Patented Nov. 2, 19h").

5 SHEETSSHEET 3- nuculor- QXJitneoow P'. M. KUEHN.

SCREENING APPARATUS.

APPLlCATION FILED DEC.29. 1914.

1,1593 1 8, Patented Nov. 1915.

5 SHEET$SHEET 4.

duo; MMPFQ .75. EMA? P. M. KUEHN.

SCREENING APPARATUS.

APPLICATION FILED DEC.29. 914.

Patented Nov. 2, 1915.

5 SHEETS-SHEET 5= PAUL M. KUEHN, F BALTIMORE, MARYLAND, ASSIGNOR TO THE BARTLETT HAYWARD COMPANY, OF BALTIMORE, MARYLAND, A CORPORATION OF MARYLAND.

SCREENING APPARATUS.

Specification of Letters Patent.

Patented Nov. 2, 1915.

Application filed December 29, 1914. Serial No. 879,440.

- citizen of the United States, residing at Baltimore, in the State of Maryland, have invented certain new and useful Improvements in Screening Apparatus, of which the following is a specification.

This invention relates to improvements in vibrating screens and particularly has to do with shaking screens of considerable weight.

My invention is expressly designed for a screen structure wherein parallel spacedapart girders are employed between which the screens are hung so as to vibrate, and an object of the invention is to provide improved means for sustaining the screens between the girders.

Another object is to provide improved means for yieldingly suspending the screens so that the latter willpractically hang pend antly between the guiding means while the vibrating means moves the screen.

A further object is to provide an improved suspension means for the screens which will aid in retarding the movement of the screens at the end of one stroke of the latter.

Another object is to provide pivoted guiding means for the screens and to combine therewith improved gravity and inertia springs to sustain and to check the movement of the screens and thereby render the screens sensitive to vertical vibrations and thus materially aid in tumbling and shifting the materials that are being screened to enable the smaller particles to promptly work to the bottom and discharge through the smaller perforations.

Other objects and advantages will appear as will be hereinafter pointed out.

The invention is illustrated in the accompanying drawings in which,

Figures 1, 1 and 1*, show the improved machine in top plan. Figs. 2, 2 and 2, illustrate the same in side elevation. Fig. 3. shows an end elevation of the girders and the screen suspended between the same, and also shows the crank-shaft in side elevation. Fig. 4:, illustrates in side elevation and on an enlarged scale an end of one of the suspension arms and the suspension spring and bracket for holding the latter. Fig. 5, shows an enlarged detail of one of the inertia springs; the manner of its engagement with a hanger arm and the means employed to connect it with a stationary cross bar of the machine. Fig. 6, als0 shows an enlarged detail of an end'of one of the springs employed. Fig. 7, shows a-detail side view of one of the. grooved spring-end engaging head's. Fig. 8, shows a side elevation of the girder, a screen and a form of suspension and inertia springs operatively connected to the same hanger bar. Fig. 9, illustrates a longitudinal sectional detail through the form of springs shown in Fig. 8,'the section beingta-ken on the line 99' of Fig. 8. Fig. 10, shows an enlarged. side view of the same, and Figs. 11 and 12, illustrate side and end elevations respectively of a vertical form of suspension spring for yieldingly suspending the screen. Y

Referring to the drawings the numeral 13, designates two spaced apart parallel girders constructed -of structural steel and prefers ably tied together at the top by suitable cross-bars in order that there shall be no independent displacement of one girder with respect to the other. Each girder wall is provided with a. plurality of bearing plates 1-l,-the plates secured to one girder wall being directly opposite, and in horizontal and vertical alinement with the corresponding plates on the other girder wall, so that rods 15, may extend horizontally across the space between the two girders and have their ends sustained in said alined bearing plates. Each rod pendantly sustains two hanging guide arms 16,the "arms being sustained at opposite ends of the rod and at the inner side ofv each girder. These guide arms are provided with loops 17, at their upper and lower ends which form bearing eyes 18, and the loops and eyes at the upper ends are engaged by the horizontal rods 15, so that said arms may hang pendantly from said rods. It will therefore be understood that on the inner side of one girder there will be a series of guide arms hanging pend.- antly from the rods 15, and on the inner side of the other girder there will be another series of guide arms also depending from the said rods.

In the present illustration, the machine is shown as employing two scre'ens 24 and 25 respectively, of substantially the .same'construction with the exception of the screening perforations 28, which latter increase in size 1 the material that is being screened. Each screen-frame has two side walls 26, and a bottom 27,the screening perforations 28, being provided in the bottom in groups and each group differing in size. The side walls of the screen frames are preferably connected across the top by suitable cross-bars .29, while at the under side of the bottom there are provided horizontal angle bars.30, which also connect the side walls. Diagonal stay bars 19, may also be provided at the upper sides of the side walls of the screen so that said latter bars, the angle bars and the said cross-bars may rigidly tie the two side walls of the screen frames together. The outer ends of the bottom angle bars 30, are provided with spindles 32, whichlatter are so arranged with, respect to the lower ends of the pendant guide arms 16, that the eyes 18, in said lower ends may be engaged with the spindles and thus pivotally engage the screen frames from the pendant guide arms. It will thus be understood that the guide arms are pendantly sustained from the horizontal cross-rods and that the screen frames extend longitudinally between the girders and also between the two sets of guide arms and that the lowerpendant ends of the guide arms are pivotally engaged by spindles that are carried by and extend horizontally from beneath the screen frames. The screen frames therefore have an elevated position above the lower ends of the pendant guide arms.

The screen frames 24 and 25 are to be oscillated, and by preference, one frame will be given a movement in one direction while the other frame is being moved in a reverse direction thereby effecting a distribution of the strains throughout the entire supporting structure. Briefly stated, movement of the screens is obtained through the rotation of a crank shaft 33, that extends horizontally beneath the lapped ends of the screens and is sustained in bearing blocks 34, as shownin Figs. 1 2 and 3 of the drawings.

The shaft 33, is provided with two sets of cranks 35 and 36, respectively so that connecting rods 37,.may engage the cranks 35, and extend rearward to the screen frame 24, while two other connecting rods 38, may engage cranks 36, and extend forward to the screen frame 25. The means employed to connect the rods 37 and 38 to the screen frames is not essential, but in the present instance comprises bracket plates 39, having studs 40, so the ends of the rods may pivotally engage the studs. The crank shaft 33, is driven, in the present instance by means-of a pulley 41, and a belt 42.

One object of the present invention is to provide means for yieldingly suspending the screen frames so that the latter will hang pendantly between and simply be guided by, the arm 16, during any back or forth movesprings to some of the this oscillating upper end of springs ment that may beimparted to the frames.

The means employed to yieldingly suspend the screen frames may vary in construction as readily shown in Figs. 4, 10 and 11 of the drawings.

In Figs. 1, 1 2, 2 and 4 the yielding suspension means comprises coiled springs 43, which, as shown in said views have inclined positions at opposite sides of the screen frames. The upper end of each spring has several of its coils wound around a circular head 44, shown in Fig. 7, which head has a spiral groove or recess 45, into which said several coils seat. A circular cavity 46, is provided in the head at the upper end of the spiral groove so that a hook 47, on the extreme end of the spring, as clearly seen in Fig. 6, may project inwardly and enter said cavity. Each head 44, has a screw-threaded post 48 extending from one end thereof, for a purpose presently to be explained. I

On the inner side ofeach girder wall 13, there are secured a plurality of angle brackets 49, which latter are perforated so that the threaded posts '48, may freely project 50, and lock nuts 51, on the post at opposite sides of the angle bracket, serve to rigidly secure the post to the bracket. The lower ends of the suspension springs 43, are to be secured to some part thathas connection with the screen frame, and in thecase of spring 43, just described, I have found it convenient to connect the lower ends of said guide arms 16. In making this connection, as shown in Fig. 4, I make use of another head 52 with a post 53, which head and post are preferably constructed precisely like the head 44, and post 48. The lower end of spring 43, is therefore wound about and secured to said head 52, and the post 53, passes freely through the lower end of one of the guide arms 16, near the lower eye 18, thereof. Adjusting and lock nuts 50 and 51, are also provided on post 53, so that by adjusting posts 48, at the 43, and, if necessary also adjusting posts 53, at the lower ends of said springs, the latter may be stretched sufliciently to take the load of the screens ofi' the guide arms normally in a forwardly-inclined position, as clearly shown in Figs. 2, 2 and 4, of the drawings. By meansof this yielding suspension of the screens the arms 16, are relieved of any duty except that of guiding the screens during any forward or backward oscillation and the screens are thereby made sensitive to Vibration in a vertical direction that materially aids in tumbling and shifting the materials that are being screened so that the smaller particles may work to the bottom and discharge through the smaller therethrough. Suitable adjusting nuts 16, and thereby yieldingly suspend the screens and hold the guide arms perforations in the bottom of the screen. It

is not essential that the suspension springs have an inclined position at the sides of the screens, or that those springs have their lower ends attached to the girder arms 16, for it is the yielding suspension of the screens that I desire to have, whether those springs are inclined, or whether they are vertically arranged, as shown in Figs. 11 and 12 of the drawings.

By referring to Figs. 11 and 12, it wil be noted that the yielding suspension springs 54:, are vertically arranged,the lower end of the spring being connected to an exteriorly grooved head 55, which latter is preferably pivotally connected to the threaded post 56. The post, in this instance, is secured tothe projecting end of an angle bar 57, that extends horizontally beneath the screen frame. This vertical form of suspension spring 54, has its upper end in wound engagement with an exteriorly grooved head 58, which latter is pivotally connected to a threaded post 59, that depends from 'a horizontal cross-bar 60, above the screen frame. When this vertical form of suspension spring 54, is employed the guide arms 16, hereinbefore described will also be employed to simply guide and direct the screens when the latter are oscillated. so that it will be seen that it is entirely unnecessary that the lower ends of the suspension springs be connected to the guide arms,

which latter need only perform the function of guiding the screens. In both cases, the suspension devices are normally under tension because they are stretched by the weight of the screens and constantly tend to draw the screens upward.

It will be noted that the apparatus above described, being constructed of metal, is quite heavy, and it is therefore desirable that the strains, caused by the oscillation of the screens, be well distributed over the stationary supporting structure or girders. It is also desirable that some means be provided to relieve the apparatus of shock caused by a change in the direction of travel of the screens.

With these objects in view I have arranged the yielding suspension springs so they will perform the double function of yieldingly suspending the screens, and also of checking the travel of the screens near the end of the stroke of the latter, in one direction.

As hereinbefore explained, the two screens have their adjacent ends lapped, the screen 25, at the receiving end being in a plane slightly higher than the screen 24:, at the discharge end and the discharge end of screen 25, overlapping the receiving end of screen 24. It has also been explained that the two screens are simultaneously oscillated,one in one direction and the other in a reverse direction. When the crankshaft 33, operates to move screen 24:, in a tension .serves to check the movement of screen 25. Thus it will be understood that in one direction of travel. the suspension springs 43, will aid in the movement, but in a reverse direction of the screens those springs will aid in checking the movement.

In order that a yielding check be provided for the screens on that stroke when the suspension springs are aiding in the lift I employ what I. term inertia springs. The application of these inertia springs to the screen parts may also vary, as will presently be shown, but by reference to Figs. 1 to 3 and to Fig. 5, an arrangement of these inertia springs will be explained.

Horizontal bars 61, extend beneath the screen frames and have their ends secured to the side girders 13. These rods are located at spaced-apart intervals and, prefer ably, have position in vertical planes between the angle brackets 49, that are attached to the girders for sustaining the upper ends of the suspension springs. Heads 62, having eyes 63, are carried on the bars 61, at each side of the screen frame,that is, in a vertical plane between the outer side of the screen frame and the inner side 'of the girder. These heads 62, like heads, 4; and 53, heretofore referred to, have exterior spiral grooves 64, so that the lower end of an inertia spring 65, may be wound around said groove and engaged therewith. The upper end of each inertia spring 65, has a wound engagement with a grooved head 66, as seen particularly in Fig. 6, of the drawings, and this latter head is provided with a threaded stem 67 that passes through the lower end of one of the guide arms 16, and is adjustably secured to said arm by means of nuts 68. While the engagement of the inertia springs with respect to the screens is made through the guide arms 16, this is merely a matter of selection and preference, because the arms are there and can be readily utilized. These springs 65, are normally inert, but when the screens are moved in a direction that would tend to compress these springs, which is when the suspension springs are stretching, those springs 65, will compress sufficiently to relieve the suspension springs by checking the motion'of the screens.

In practice, the motion of each screen is only about two to four inches, more or less, therefore, the work which the springs are called upon to do is well within their power. These inertia springs are not of necessity collar attached to the guide arms, as heretofore explained, nor is it necessary, when they are attached to those arms, that they be connected at theunder sides of the arms, as will now be explained in connection with Figs. 8, 9 and 10 of the drawings. In said figures it will be noted that the suspension spring 43, is connected to the girder 13, by means of the angle bracket 49, grooved head 4.4, and threaded post 48, precisely as shown in Figs. 1, 1 2, 2 and Fig. 4. It will also be noted that the lower end of the suspension spring is connected to a guide arm 16, also as heretofore explained. The only difference in these connections is that the head 69, which makes the connection with the arm 16, in these Figs. 8, 9 and 10, has two exterior diameters and two sets of spiral gro0ves,the grooves around the smaller diameter of the head receiving the coils at the lower end of the suspension spring and the 70, serving to engage the lower end grooves of a larger inertia spring 72. In thislnstance, the larger inertia spring encircles.

the lower end of the suspension spring and the lower ends of both springs coact with the same girder arm. The upper end of this larger inertia spring 72, engages a flanged collar 7 3, through a central opening 74, of which the suspension spring freely passes, as clearly shown in Fig. 9. 1 This 73, is bolted to a perforated angle bracket 75, that is rigidly attached to the girder 13. It will therefore be seenthat in this arrangement, the suspension and inertia springs have a single connection that secures their lower ends with respect to a part that moves with the screen and have their upper ends independently connected to the girder wall. In this arrangement of springs it will also be noted that both springs have positions above the lower end of the guide arm, to which it is found convenient to connect them.

The inertia spring 72, when the screens and guide arms are in the normal position shown in Figs. 8, 9 and 10, are simply inert, being neither under tension or compression, but capable of being either compressed or stretched to the limited extent necessary in the apparatus disclosed. Therefore when the screen is moved forward, suspension springs 43, will relax while the inertia springs 72, will be slightly compressed against collar 73, which compression will check the movement of the screenand take up shocks. On a return or reverse stroke however these inertia springs 72, will assume a normal inert con ition and any tendency of the screens to move beyond that would require those springs to stretch which would also act to check the movement of the screens in this reverse movement.

By means of the present invention the screens are yieldingly suspended and therefore comparatively sensitive; they are guid ed by the pendant guide arms so their movement will be in an arc which efiects a tumbling of the materials and the arrangement of springs is such that the screens are checked at the ends of their strokes which further aids in the tumbling and which also takes up shocks during the change of motion of the screens. Having thus described my invention what I claim is,--

1. In a screening apparatus the combination with spaced apart girders, of a screen frame between the girders; a series of guide arms between the inner sides ofthe girders and the outer sides of the screen frame said guide arms having their upper ends, pivoted with respect to the girders and their lower ends pivotally connected to the screen; a series of suspension springs between the screen and the girders and a series of inertia springs also between the screen and girders.

2. In a screening apparatus the combination with spaced apart girders, of a screen frame between the girders; reciprocating means for moving the screen back and forth; guide arms having their upper ends pivoted with respect to the girders and their lower ends depending between the girders and screen and pivotally connected to the latter; a series of springs between the sides of the screen and the girders said springs having their upper ends secured with respect to the girders and their lower ends connected with the screen and another series of springs between the girders and the screen and each having one end secured with respect to the girders and the other end connected to the screen.

3. In a screening apparatus the combination with spaced apart girders, of a screen between the girders; a series of guide arms along each side of the screen and each guide arm having an upper end pivoted with respect to the girders and a lower end pivoted to the screen; springs interposed between the sides of the screen and the girders and each spring having an end secured-with respect to the girders and another end connected with a guide arm.

4. In a screening apparatus the combination with spaced apart supports, of a screen between the supports; stifl' unyielding arms for pivotally connecting the screen and the supports; springs for suspending the screen; coiled springs interposed between the sides of the screen and the supports for checking the movement of the scree'n in one direction and reciprocating means for moving the screen back and forth.

5. In a screening apparatus the combination with spaced apart supports, of a screen between the supports; stiff unyielding arms for pivotally connecting the screen and the supports; coiled springs between the sides ion of the screen and the supports said springs each having one end secured with respect to the supports and the other end connected to a pivoted arm; reciprocating means for moving the screen back and forth, and another set of coiled springs interposed between the supports and the screen to check the movement of the latter.

6. In a screening apparatus the combination with spaced apart parallel supports, of

a screen extending longitudinally between said supports; swinging guide arms each having an upper end pivotally connected with respect to the supports and a lower end pivotally connected to the screen; a set of coiled springs along eachside of the screen to suspend the latter and hold the guide arms in an inclined position; another set of coiled springs along the sides of the screen and each of the latter springs having one end secured with respect to the supports and the other end connected to a part moving with the screen to check the movement of the latter and reciprocating means for moving the screen in a direction that relieves the suspension springs and then in a reverse direction to be acted upon by the said other set of springs.

7. In a screening apparatus the combination with spaced apart parallel supports, of a screen'extending longitudinally between said supports; swinging guide arms each having an upper end pivotally connected with respect to the supports and a lower end pivotally connected to the screen; a set of coiled springs along each side of the screen each spring of the set having one endsecured with respect to the supports and another end connected tov a swinging guide arm; another set of coiled springs along each side of the screen and each spring of this latter set having one end secured with respect to the support and its other end secured to a swinging arm, and reciprocating means for moving the screen back and forth.

8. In a screening apparatus the combination with a support, of a screen; means for moving the screen back and forth; swinging guide means having one end pivoted with respect to the support and its other end pivotally connected to the screen; a set of coiledsprings each having a lower end adjustably connected to a swinging guide means whereby to suspend the screen and another set of coiled springs each also having an end adjustably connected to a swinging guide means, to check the movement of the screen.

9. In a screening apparatus the combination with a screen, of means for moving the screen back and forth; pivoted Ineansmoving with the screen for guiding the latter during its travels and coiled springs engaging the pivoted guiding means to yieldingly suspend the screen through the guiding means.

10. In a screening apparatus the combination with a screen, of means for moving the screen back and forth; pendant guiding means having a pivoted connection with the screen and moving with the latter; coiled spring suspension means having engagement with pendant guiding means and coiled springs also having connection with pendant guiding means for checking the movement of the screen. I

11. In a screening apparatus the combination with a screen. of means for moving'the screen back and forth; swinging arms for guiding the screen during its movement; two sets of coiled springs each having a connection with apart moving with the screen; means for holding one coiled spring normally stretched to yieldingly sustain the screen, and means for normally holding the other spring inert.

12. In a screening apparatus the combination with a screen, of means for moving the screen back and forth; means for guiding the screen; two coiled spring each having one end connected to a part moving with the screen; means for normally holding one spring stretched and means for forming an abutment in the path of the other spring.

13. In a screening apparatus the combination with a screen, of means for moving the screen back and forth; means for guiding the screen; two coiled springs one encircling an end of the other and each spring having one end connected to a part moving with the screen; means for normally holding the spring with the encircled end in a stretched condition and means between the ends of the spring whose end is encircled to form an abutment for the encircling spring.

In testimony whereof I afliX my signature in presence of two witnesses,

PAUL M. KUEHN.

\Vitnesses GEO. E. PROBEST, Jr., 'IHos. BUTTERWORTH. 

